Chapter 3: Biological Molecules

• Carbohydrates, fats, and proteins are the three major types of nutrients found in living organisms
• Water


  An essential component of all body tissues, making up 70% of our body weight. It is a solvent for chemical reactions, essential for photosynthesis, helps regulate body temperature, and transports dissolved substances around the body.
• Carbohydrates


  Biological molecules that serve as nutrients essential for living organisms. They can be classified as single sugars, double sugars, or complex carbohydrates.
• Single sugars


  • Basic units of carbohydrates, small enough to pass through cell membranes. Examples are glucose and fructose.
• Double sugars


  • Formed when two single sugars are joined together. Examples are maltose and sucrose.
• Splitting of double sugars


  Double sugars can be split into two single sugar molecules in the presence of an enzyme.
• Reducing sugars


  Glucose, fructose, and maltose are examples of reducing sugars.
• Benedict's test for reducing sugars


  Add Benedict's solution to food sample, heat in boiling water bath. Green, yellow or red precipitate indicates presence of reducing sugars in trace, moderate or large amounts respectively.
• Cellulose, glycogen and starch are synthesized from glucose
• Complex carbohydrates


  • Consist of many molecules of single sugars joined together. Examples are starch, cellulose, and glycogen.
• Starch


  Storage form of carbohydrates in plants, made of thousands of glucose molecules joined together.
• Cellulose


  Glucose molecules joined differently than in starch, forms cell walls that protect plant cells and serves as dietary fiber.
• Glycogen


  Branched molecule of many glucose molecules, storage form of carbohydrates in animals.
• Functions of carbohydrates


  • Provide energy, form supporting structures, convert into other organic compounds, form nucleic acids, synthesize lubricants and nectar.
• Iodine test for starch


  Add iodine solution to food sample, if starch is present the solution turns blue-black.
• Carbohydrates


  One of the key biological molecules required to build structures that enable organisms to function
• Proteins


  One of the key biological molecules required to build structures that enable organisms to function
• Lipids


  One of the key biological molecules required to build structures that enable organisms to function
• Nucleic Acids


  One of the key biological molecules required to build structures that enable organisms to function
• Water


  One of the key biological molecules required to build structures that enable organisms to function
• Monomers


  Smaller units from which larger molecules are made
• Synthetic polymers


  • nylon
  • polyethylene
  • polyester
  • Teflon
  • epoxy
• Enzyme catalysis


  1. Substrate binding

  2. Transition state facilitation

  3. Catalysis

  4. Release
• Enzymes


  • They increase the rate of chemical reactions without themselves being consumed or permanently altered by the reaction
  • They increase reaction rates without altering the chemical equilibrium between reactants and products
• As temperature increases


  The rate of reaction increases
• When analysing markets, a range of assumptions are made about the rationality of economic agents involved in the transactions
• The Wealth of Nations was written


  1776
• Rational


  (in classical economic theory) economic agents are able to consider the outcome of their choices and recognise the net benefits of each one
• Producers act rationally by


  Selling goods/services in a way that maximises their profits
• Governments act rationally by


  Placing the interests of the people they serve first in order to maximise their welfare
• Rationality in classical economic theory is a flawed assumption as people usually don't act rationally
• A firm increases advertising


  Demand curve shifts right
• Demand curve shifting right

  Increases the equilibrium price and quantity
• Marginal utility


  The additional utility (satisfaction) gained from the consumption of an additional product
• If you add up marginal utility for each unit you get total utility
• Fats are biological molecules that serve as nutrients that are essential for living organisms
• Fat molecule


  Made up of glycerol and fatty acid chains
• Sources of fats


  • Butter
  • Corn oil
  • Olives
  • Nuts and their oils
• Functions of fats


  • Source and store of energy
  • Insulating material to prevent excessive heat loss
  • Solvent for fat soluble vitamins and some hormones
  • Form the main part of cell membranes
  • Help reduce water loss from skin surface
• Eskimos traditionally spend most of the year hunting for animals, including whales, seals, walrus and polar bears and often eat them raw